What happened
On June 18, 2011, a Cessna 206 G, registration F-GDAA, was performing its ninth skydiving mission of the day from Saint-Etienne Bouthéon aerodrome. While climbing through an altitude between 4,000 and 5,000 feet, the pilot heard a loud noise coming from the engine, accompanied by significant vibrations and oil spraying onto the windshield.
Following established emergency procedures for an in-flight engine shutdown, the pilot executed a forced landing on the runway. The engine ceased operation during the landing roll.
The investigation
Investigators examined the Continental IO-520F engine and discovered two perforations in the upper crankcase near cylinders number 3 and 4. Detailed disassembly and inspection revealed that the engine failure was caused by the failure of the connecting rod for cylinder number 4 at its attachment point to the crankshaft.
Records showed the engine had been manufactured and installed on F-GDAA in 2004. Between February and April 2011, the engine underwent a major overhaul, which included a magnetic particle inspection (magnaflux) that failed to detect any fatigue cracks. At the time of the accident, the engine had accumulated 1,330 total operating hours, with only 63 hours and 29 cycles completed since the overhaul.